Unit 1-Molecules of life

Acid

A substance that increases the hydrogen ion (H+) concentration in a solution

Adhesion

The attraction between different kinds of molecules

Aqueous solution

A solution in which water is the solvent

Atom

Is the smallest unit of matter that still retains the properties of an element

Atomic mass

Neutrons + protons, the total mass of an atom

Atomic number

The number of protons in each atom of a particular element

Base

A substance that decreases the hydrogen ion (H+) concentration in a solution

Biology

The study of life

Buffer

A chemical substance that minimizes change in pH by accepting hydrogen ions from or donating hydrogen ions to solution

Compound

A substance containing two or more elements in a fixed ratio

Chemical bonds

An attraction between two atoms resulting from a share of outer-shell electrons or the presence of opposite charges on the atoms

Chemical reaction

The making and breaking of chemical bonds, leading to changes to changes in the composition

Cohesion

The sticking together of molecules of the same kind, often by hydrogen bonds

Covalent bond

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons

Electron

A particle with a single negative electrical charge

Electron shell

A level of electrons at a characteristic average distance from the nucleus of an atom

Electronegativity

Is measure of its attraction for shared electrons

Element

A substance that cannot be broken down to other substances by chemical means

Heat

Thermal energy in transfer from one body of matter to another

Homeostasis

The self-regulating ability of a living organism to maintain a stable internal environment

Hydrogen bond

A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond is attracted to the slightly negative atom of a polar covalent bond

Hydration shell

A layer of water molecules that surrounds and interacts with an ion or a polar molecule in a aqueous solution

Ion

An atom or molecule that has gained or lost electrons, resulting in a net electrical charge

Ionic bond

A chemical bond resulting from the attraction between opposite charge ions, the actual transfer of an electron between atoms

Isotope

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons

Mass number

The sum of the number of protons and neutrons in an atoms nucleus

Matter

Anything that occupies space and has mass

Molecule

Two or more atoms held together by covalent bonds

Neutron

A particle having no electrical charge, found in the nucleus of an atom

Nonpolar covalent bond

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity

Nucleus (of atom)

An atoms’s central core, containing protons and neutrons

pH scale

Describe how acidic or basic a solution is, scale ranges from 0-14

Polar molecule

A molecule containing polar covalent bonds and having an unequal distribution of charges

Product

An ending material in a chemical reaction

Product

An ending material in a chemical reaction

Proton

A particle with a single positive electrical charge, found in the nucleus of an atom

Radioactive isotope

An isotope whose nucleus decays spontaneously, giving off particles and energy

Reactant

A starting material in a chemical reaction

Trace element

An element that is essential for life but required in extremely small amounts

Valence electron

Solute

The substance that is being dissolved

Solution

Is a liquid constituent of a uniform mixture of two or more substances

Solvent

The dissolving agent ex:water

Surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

Temperature

A measure in degrees of the average thermal energy of the atoms and molecules in a body of matter

Thermal energy

Kinetic energy due to the random motion of atoms and molecules, energy in its most random form